The effective management and maintenance of large dairy herds and the production of dairy products has been a major agricultural accomplishment. One of the problems in maintaining large herds is the health of the individual animals. One health problem in individual animals of dairy herds which causes significant economic problems relates to mastitis. Often during milking, the skin of the dairy animal is irritated by automatic milking machines. This irritation, characterized by redness and occasionally areas of broken skin, can be the site of a microbial attack causing mastitis. Animals that contract mastitis must be removed from service resulting in the loss of the dairy output. As a result, a significant amount of attention has been focused on preventing the development of mastitis or treating mastitis in dairy herds.
The dairy farmer is faced with two different types of mastitis infections. Contagious mastitis is spread during the milking process through contact between the animal and dairy equipment that may carry a source of a mastitis pathogen. Contagious mastitis is most easily controlled using germicidal post milking teat dips. Such germicidal dips kill bacteria that are introduced onto the surface of the animal from the milking machines. The second type of mastitis, environmental mastitis, is caused by contamination of the animal surface by materials from the barn yard environment, fields, barn interior, etc. Such pathogens include E. coli, Streptococcus uberis, klebsiella and others. Such contamination occurs as the animal moves through its environment. Environmental mastitis is best treated with a barrier film that protects sensitive tissues from contamination.
In the treatment and prevention of mastitis the use of protective coatings, formed from aqueous coating systems, on the animals has been an option for many years. One class of coating compositions are actively antimicrobial and prevent the incidence of infection in the animal through the presence of an active biocide in the coating. Another class of coating materials are simply film barriers formed on the skin surface to prevent contact between vulnerable tissues and the environment. Many antimicrobial materials are incompatible with a variety of these polymeric or film forming materials. Recent product developments provide coatings for teat skin which form film barriers, as well as, contain antimicrobial agents.
In the typical operations of a dairy herd, the herd is brought into a milking station, the udder is washed to remove the barrier film. Any delay in removal of the film can substantially reduce productivity and substantially increase time required to deal with a large herd. Further, difficulty in removing the film can cause abrasion or bruising to the animal which can promote mastitis. Therefore, it is important that the films are easily removed in less than 15 minutes, preferably in less than 10 minutes, using water or mild cleaning solutions. In the periods between milking, the animal is released into the environment to graze. While grazing the animal is exposed to environmental water from dew, mud, rain and ponds. This exposure to water can cause the barrier film to rub off.
Among the materials used in barrier-type or film-type teat dips are solubilized liquids, polyvinylpyrrolidone and other vinyl polymers, protein hydrozylate, natural and synthetic gums, water, ethanol, methanol, isopropanol, soluble polymers, unsaturated fatty oils, cellulose derivatives, acrylic polymer lattices, etc.
Latex provides an effective covering of teat skin which can be combined with an antimicrobial agent (U.S. Pat. No. 4,113,854). However, the latex material has the serious drawback of not being readily removable when the next milking time arrives. The result can be a partially removed coating, leaving behind particles which become trapped in the milk line filters. The difficulties of removal can also result in excessive rubbing of the teat skin, thus leading to irritation. Furthermore the use of latex can potentially result in milk contamination.
On the other hand, teat dips which are easy to remove, for example, polyvinyl alcohol based teat dips, do not provide adequate water resistance. Such films do not remain on a dairy animal for the duration between milking periods. Due to exposure to water, these films wear off in about 3 to 4 hours. Without an adequate barrier film the dairy animal is vulnerable to environmental pathogens which will promote mastitis in the herd.
The following disclosures have been identified as part of the technology of the related art. Typical disclosures of disinfectant after-milking teat dips (aimed at destroying any pathogens remaining on the teats after milking) can be found in British Patent 1 144 637 (Kelco Chemicals, Ltd.), published on Mar. 5, 1969; Meave et al., J. Dairy Science, 52:6696 (1969); Dodd et al., `Mastitis Control,` Biennial Reviews (1970) University of Redding, England, National Institute of Research of Dairying, pp. 21-57; Lentsch, U.S. Pat. No. 4,258,056; Lentsch et al., U.S. Pat. No. 4,376,787; Yang, U.S. Pat. No. 4,446,153; Marhevka, U.S. Pat. No. 5,017,369; Cantor et al., U.S. Pat. No. 3,728,449; Pankey, `Postmilking Teat Antisepsis,` Symposium on Bovine Mastitis, Veterinary Clinics of North America: Large Animal Practice, Vol. 6, No. 2, July 1984; Pankey et al., `Efficacy Evaluation of Two New Teat Dip Formulations Under Experimental Challenge,` Journal Dairy Science, 68:462-465 (1985), Philpot et al., `Hygiene in the Prevention of Udder Infections. V. Efficacy of Teat Dips Under Experimental Exposure to Mastitis Pathogens,` Journal Dairy Science, 61:956-963 (1978), Bennett, `Teat Dip as a Component of Coliform Mastitis Control, Dairy and Food Sanitation,` Vol. 2, No. 3, pp. 110-114 (March 1982), Eberhart et al, `Germicidal Teat Dip in a Herd with Low Prevalence of Streptococcus agalactiae and Staphylococcus aureau Mastitis,` Journal Dairy Science, 66:1390-1395 (1983).
Typical disclosures of protective or barrier-type teat dips can be found in Loosemore et al., U.S. Pat. No. 5,641,498, Schmidt et al., U.S. Pat. No. 5,503,338, Acres et al., U.S. Pat. No. 3,066,071, Krause, U.S. Pat. No. 3,222,252, Philpot et al., Journal Dairy Science, 58:205-216, Coughman et al., U.S. Pat. No. 3,993,777, Pugliese, U.S. Pat. No. 4,049,830, Silver et al., U.S. Pat. No. 4,199,564, Dybas et al., U.S. Pat. No. 4,311,709 and Andrews et al., U.S. Pat. No. 4,113,854. Still also for examples of such materials, see Farnsworth, Journal of American Veterinary Medical Association, 177:441 (1980) and Farnsworth et al., The Bovine Practitioner, No. 16, pp. 28-29 (1981). Still further, please review Canadian Patent No. 1,065,254 and European Published Application No. 25,640 (Mar. 25, 1981).
A substantial need exists for an antimicrobial and barrier teat dip that can be easily and rapidly removed during milking operations while imparting sustained water resistance between milking periods.